In a semiconductor package or module, heat is generated during operation from memory and controller devices formed on a device substrate which is apart of the semiconductor package or module. The generated heat is transferred by thermal conduction from the device substrate into the substrate of the semiconductor package or module (“packaging substrate”) and by convection and radiation from the surface of the packaged device. The generated heat is also, in part, dissipated by conduction from the packaging substrate to the region outside of the module through the electrical contacts between the packaging substrate and a further module or end product and also through columns provided to fix the module to a PC casing or the like, or to a connector of the module.
Now, as high speed operation of the module and high memory capacity of module are desired, the elements on the substrate, such as the memory components and the controller, are preferred to be closely packed and the number of such elements per unit area of the substrate has been increasing. Further, the high speed operation of the controller generates more heat than does a slower operating speed thereof. As a result, the heat generated from the memory components and the controller might not be sufficiently dissipated to the outside of the module, and the quantity of heat held in the semiconductor module, and thus the operating temperature of the module, is increased.
In order to improve the reliability of the memory components and to avoid error in the operation thereof, it is necessary to maintain the temperature of the memory components in or on a substrate as low as possible. This is because as the temperature of the memory components rises, errors in the operation of the memory components occur more frequently. Further, to correct the errors, a tedious operation has to be carried out which slows down the operation of the memory components.
Thus, a semiconductor module that can perform a large capacity memory operation at a high speed and at a low temperature is demanded.